Apple denied a request from US Attorney General Bill Barr Monday evening to unlock two iPhones belonging to the Saudi Air Force cadet who killed three sailors and wounded eight others in a shooting at a naval air station in Pensacola, Florida, last month.

“We reject the characterization that Apple has not provided substantive assistance in the Pensacola investigation. Our responses to their many requests since the attack have been timely, thorough and are ongoing,” the company said in a statement. “We responded to each request promptly, often within hours, sharing information with FBI offices in Jacksonville, Pensacola and New York. The queries resulted in many gigabytes of information that we turned over to investigators. In every instance, we responded with all of the information that we had.”

But Apple said nothing about actually unlocking the gunman’s two iPhones. Instead, it reiterated its stance on privacy.

“We have always maintained there is no such thing as a backdoor just for the good guys,” the company explained. “Backdoors can also be exploited by those who threaten our national security and the data security of our customers. … We feel strongly encryption is vital to protecting our country and our users’ data.

Earlier on Monday, Barr declared that the shooting was an act of terrorism and asked the company to unlock two phones — an iPhone 7 and an iPhone 5 — belonging to the gunman, who died in a shootout with security officers.

“We have asked Apple for their help in unlocking the shooter’s iPhones. So far Apple has not given us any substantive assistance,” Barr said in a press conference. “This situation perfectly illustrates why it is critical that investigators be able to get access to digital evidence once they have obtained a court order based on probable cause. We call on Apple and other technology companies to help us find a solution so that we can better protect the lives of Americans and prevent future attacks.”

During the attack, the shooter placed one of his phones on the ground and shot a single round into it. The other phone was undamaged. Although FBI agents have been able to reconstruct the damaged phone, they have not been able to unlock it or the second phone, which Barr said the FBI needed to do to “run down all leads and figure out with whom the shooter was communicating.”

This is not the first time that Apple has squared off against federal law enforcement in defense of its users’ privacy, arguing that agreeing to such a request would require Apple to build a backdoor around its fingerprint-based encryption and set a dangerous precedent.

In 2015, Apple defied a court order to assist the FBI by unlocking the iPhone belonging to another mass shooter — one of two terrorists who killed 14 people in San Bernardino. In that case, the standoff was resolved after a private company working for the FBI found a way to unlock the phone.

“We’re not trying to weaken encryption, to be clear,” David Bowdich, the deputy director of the FBI, said at the news conference.

In his remarks, Barr suggested that the Trump administration had begun discussing legislation to provide law enforcement access to encrypted phones in cases such as these.

Barr’s request also drew criticism from civil libertarians: “The government’s demand would weaken the security of millions of iPhones, and is dangerous and unconstitutional,” ACLU surveillance and cybersecurity counsel Jennifer Granick said in a statement. “There is simply no way for Apple, or any other company, to provide the FBI access to encrypted communications without also providing it to authoritarian foreign governments and weakening our defenses against criminals and hackers.”

Update, Jan. 14:

The day following Apple’s response, President Donald Trump sharply criticized the company on Twitter: “We are helping Apple all of the time on TRADE and so many other issues, and yet they refuse to unlock phones used by killers, drug dealers and other violent criminal elements,” he wrote on Tuesday evening.

Apple’s statement in full, below:

We were devastated to learn of the tragic terrorist attack on members of the US armed services at the Naval Air Station in Pensacola, Florida on December 6th. We have the greatest respect for law enforcement and routinely work with police across the country on their investigations. When law enforcement requests our assistance, our teams work around the clock to provide them with the information we have.

We reject the characterization that Apple has not provided substantive assistance in the Pensacola investigation. Our responses to their many requests since the attack have been timely, thorough and are ongoing.

Within hours of the FBI’s first request on December 6th, we produced a wide variety of information associated with the investigation. From December 7th through the 14th, we received six additional legal requests and in response provided information including iCloud backups, account information and transactional data for multiple accounts.

We responded to each request promptly, often within hours, sharing information with FBI offices in Jacksonville, Pensacola and New York. The queries resulted in many gigabytes of information that we turned over to investigators. In every instance, we responded with all of the information that we had.

The FBI only notified us on January 6th that they needed additional assistance — a month after the attack occurred. Only then did we learn about the existence of a second iPhone associated with the investigation and the FBI’s inability to access either iPhone. It was not until January 8th that we received a subpoena for information related to the second iPhone, which we responded to within hours. Early outreach is critical to accessing information and finding additional options.

We are continuing to work with the FBI, and our engineering teams recently had a call to provide additional technical assistance. Apple has great respect for the Bureau’s work, and we will work tirelessly to help them investigate this tragic attack on our nation.

We have always maintained there is no such thing as a backdoor just for the good guys. Backdoors can also be exploited by those who threaten our national security and the data security of our customers. Today, law enforcement has access to more data than ever before in history, so Americans do not have to choose between weakening encryption and solving investigations. We feel strongly encryption is vital to protecting our country and our users’ data.